The 'inventor' of bifocals? The 'inventor' of bifocals? The Politician, Stephen Elmer, 1777 US statesman Benjamin Franklin has long been credited with the invention of bifocal spectacle lenses, but whether this is historically accurate or merely a myth is a matter of debate. Most serious historians now agree that the hard evidence is lacking. Benjamin Franklin, writer, politician, scientist and optician, was a great advocate of air bathing and is known to have favoured sitting naked each morning before an open window. Presumably he did not curtail this activity while lodging at what is now number 36 Craven Street (a few doors down from the present College of Optometrists' headquarters) between 1757 and 1775. Franklin can still be seen in the street (fully clothed) in this oil painting by royal academician Stephen Elmer, dated 1777. The portrait was acquired by the Museum in 1939. A subsequent copy of the painting is also on display at the US Embassy building in Paris.

Franklin is known to have worn temple spectacles after his arrival in England, as must have done other members of his family. In February 1757 he wrote to his wife Deborah Franklin to describe the new furnishings in his Craven Street lodgings: 'Look at the figures on the China Bowl and Coffee Cups, with your spectacles on; they will bear examining'. In this painting, however, he is shown wearing silver folding nose spectacles, a precursor of pince-nez, but the College's interest in this portrait stems not from the eyewear depicted, but from the claim that Franklin was the inventor of the split-bifocal lens. The idea of a split lens, for use as a trial lens rather than for spectacles, had been suggested by Zahn in 1683 and, again, by Hertel in 1716, but there is no evidence that such lenses served a practical, ophthalmic function until several decades later. Franklin wore spectacles continually after 1776. He admitted in 1784 that without them he could not 'distinguish a letter even of large print'.

In 1779, whilst on his diplomatic mission to France which lasted from 1777-1785, Franklin had ordered a pair of spectacles from the English optician, Sykes, who had a business on the Place du Palais-Royale. The fact that Sykes wrote to Franklin explaining that his spectacles had been delayed due to the lenses having broken three times during cutting has been taken as evidence that the ambassador was ordering something out of the ordinary. The price of 18F, which he paid for the spectacles, was certainly higher than was usual at the time. In a letter of August 1784, written to his friend George Whatley, Franklin declared himself 'happy in the invention of double spectacles, which serving for distant objects as well as near ones, make my eyes as useful to me as ever they were'. It should be noted that he did not describe them as 'my' invention, nor should the wording be taken necessarily to mean that the invention was recent. Whatley replied, referring to the spectacles as 'your invention' and as something he had been discussing with the English optician, Peter Dollond.

The Dollonds were, it seems, producing spectacles of this, or a similar, type, as a bespoke service, but were not convinced that the idea had commercial potential. Bifocal spectacles were described in a further letter of Franklin's to Whatley, dated 23 May 1785. In this he again referred to 'my double spectacles' (where 'my' need only signify ownership) and provided a sketch. The letter continued: 'The same convexity of glass, through which a man sees clearest and best at the distance proper for reading, is not the best for greater distances. I therefore had formerly two pair of spectacles, which I shifted occasionally, as in travelling I sometimes read, and often wanted to regard the prospects. Finding this change troublesome, and not always sufficiently ready, I had the glasses cut and half of each kind associated in the same circle.

By this means, as I wear my spectacles constantly, I have only to move my eyes up or down, as I want to see distinctly far or near, the proper glasses being always ready.' A modern replica pair of the type of split bifocal spectacles known to have been worn by Benjamin Franklin in the mid 1780s Some historians, however, have suggested that in this letter to Whatley, Franklin refers to an experiment carried out more than 20 years earlier in London. A letter from the newspaper editor, John Fenno, to his wife dated 8 March 1789, supports this theory. In it Fenno describes a meeting with Franklin in which the elderly statesman had mentioned wearing the spectacles over many years: 'He informed me that he had worn spectacles for 50 years; each eye appeared to be formed of two pieces of glass divided horizontally - he informed me that he had always worn such'. The Fenno letter also fits in with the fact that Franklin suffered from hyperopia, requiring spectacles for this condition as early as the 1730s. This would have made him likely to have benefited from bifocals by the time he arrived in London in 1757.

Before leaving the America the first time Franklin had clearly had an interest in optical developments. He imported vision aids and advertised 'spectacles of several sorts' in the Pennsylvania Gazette. Our knowlege that he was involved in the supply of spectacles in his early adult life may cause us to consider that he may well have had the interest to experiment with bifocals at an earlier date. Yet the only portrait of Franklin in which he is depicted wearing bifocals is one by Charles Willson Peale, dated 1785, when the old man was aged 81 and living once again in Pennsylvania. This does at least suggest that we would be right to say that Franklin introduced bifocals to America. Wider public awareness of the invention only came about in the early 1790s, following Franklin's death. A genuine pair of split bifocal spectacles, possibly c.1790s though the sliding sides mean we cannot guarantee they are any earlier than 1806 During this period several authors published the Whatley letter, thereby cementing in the public mind the link between bifocals and Franklin.

Peale, having painted Franklin wearing bifocals, is known to have made his own pair in 1788 and may have been responsible for introducing the concept to the first US optician, John McAllister, some time after 1799. The idea for bifocal spectacles, attributed by some people to Franklin in both Britain and the US, (though never patented by him or anyone else) soon led to further developments. The use of hinged supplementary visors (to hold reading lenses) was patented in London by John Richardson in 1797. By 1836 Isaac Schnaitman, a German immigrant to Philadelphia, had taken out a patent on one-piece lenses with both distance and reading portions ground on to one piece of glass. Another claimant to the title? Benjamin West (1738-1820), an American artist, originally from Philadelphia was a natural friend for Franklin in London. He woul;d later become President of the Royal Academy from 1792-1815. West is known to have been an early wearer of 'divided glasses' or bifocals, possibly before 1800, but probably not before Franklin.

That has not stopped historians pushing the claim of West or his predecessor at the Royal Academy, Sir Joshua Reynolds, to have 'invented' bifocals in the 1760s. Why anyone should be so determined to attribute their invention to a prominent named individual is perhaps the more baffling question. It does seem likely, however, that these men, especially West, were using split lenses supplied by London opticians for artistic purposes, if not for normal vision, and that this may have prompted Franklin to order some. The Definitive Word...for now Unless further evidence emerges all we can say for certain is that Franklin was one of the first people to wear split bifocals and this act of wearing them caused his name to be associated with the type from an early date. This no doubt contributed greatly to their popularisation. The evidence implies, however, that when he sought to order lenses of this type the London opticians were already familiar with them. Other members of Franklin's circle of British friends may have worn them even earlier, from the 1760s, but it is at best uncertain (and arguably improbable?) that split bifocal lenses had a famous gentleman inventor.

Why not combine your visit to the museum at the College of Optometrists with a visit to our near neighbour, the Benjamin Franklin House , the only surviving Franklin residence in the world? Who Invented Eyeglasses? - Who was Glasses Inventor? Home » Glasses Inventor » Who Invented Glasses? Eyeglasses Inventors - Who Invented Glasses? There are many dilemmas about invention of glasses. According to some sources the invention of the first wearable pair of eyeglasses occurred in the 13th century in Italy. Salvino D'Armate probably invented eyeglasses in around 1285, though various sources suggest an earlier origin. He shared the invention of his new device with Allesandro della Spina, an Italian monk, who made it public and is often credited with inventing eyeglasses. The first eyeglasses had frames made of metal or bone and had lenses made out of quartz because the ''opticians'' of that time didn't have the capabilities of producing flawless lenses in glass. In the 14th century, Venetian craftsmen were making "disks for the eyes"'.

Italians gave these glass disks that were finely ground the name lenses because they were similar in shape to lentil beans. The earliest lenses were convex, the bulged outward in the middle, and they were used to correct far-sightedness. By the fifteenth century, spectacles had found their way to China. In 1451 Nicholas of Cusa in Germany produced eyeglasses to aid people who were near-sighted using concave lenses that were thinner at the center and thicker at the ends. Early eyeglasses had glass lenses set into heavy frames of wood, lead or copper. Natural materials of leather, bone and horn were later used for production of frames. In the early seventeenth century, lighter frames of steel were invented. The modern style of eyeglasses frame, which could be placed over the ears and nose, was invented in 1727 by British optician Edward Scarlett. American scientist and philosopher Benjamin Franklin is credited with the invention of bifocals, dividing his lenses for distant and near vision. These two lenses were held together in a metal frame.

Sir George Biddle Airy, an English astronomer and mathematician, invented glasses to correct astigmatism in 1827 which were meant to be held by hand. Later glasses were designed to be held in place by ribbon or by exerting pressure on the bridge of the nose, such as with pince-nez. Construction of frames also improved over the centuries, and today they are made in wide array of styles and designs. Frames are generally produced of metal or plastic, and lenses are produced of glass or plastic. In 1955 the unbreakable lenses were invented and in 1971 a new lens were developed which combined the properties of plastic with glass. Copyright© Glasses History Who Invented Bifocal Glasses Who Invented Bifocal Glasses 01 Aug, 2011 who invented 0 Bifocal glasses are designed with 2 different lenses in the one pair of glasses. They are generally used by people who have diminished eyesight and also require correction for nearsightedness. This allows the wearer to see clearly at all times, while also providing focus for tasks such as reading.

Traditionally they were made of two separate lenses, but today a small section for reading is molded into the main lens. Who invented bifocal glasses? Although there has been some debate about the inventor of this type of glasses, the invention is generally credited to Benjamin Franklin. No one knows when he invented the first pair of bifocal glasses, but recent evidence suggests that it could have been earlier than most historians once believed. He visited France on a diplomatic mission between 1777 and 1785. In 1779, evidence suggests that he ordered a special pair of spectacles from an English optician, which is now believed to be a pair of bifocal glasses. However, there is some evidence to suggest that he could have been wearing bifocal glasses much earlier. A newspaper editor, named John Fenno, met with an elderly Franklin who told him that he had been wearing bifocals for 50 years. The term bifocals didn’t originate until 1824 when John Isaac Hawkins invented trifocal glasses. He named Benjamin Franklin’s lenses bifocal.

Related Articles Benjamin Franklin-Father of the Bifocal Benjamin Franklin-Father of the Bifocal + Larger Font | - Smaller Font Adapted from the important key article by Dr. Charles Letocha, also the wonderful book by Dr. John Levene and finally the comprehensive paper (yet unpublished) by Stuart Green. In 1990 the year of the bicentennial celebration of Benjamin Franklinâ€™s death (1706-1790) a comprehensive article was published by Dr. Charles Letocha, â€œThe Invention and Early Manufacture of Bifocalsâ€�. It presented Benjamin Franklin as the inventor of bifocals. It is still considered the definitive paper on this topic because no new information has surfaced to the contrary during the past 15 years. This current year 2006 is the tercentenary of Franklinâ€™s birth and therefore we can again recognize Franklin for his major role in the development of bifocal eyeglasses. No one else deserves this esteemed honor: Ben Franklin-Father of the Bifocal. The invention of bifocals had been reviewed in great detail by Dr. John R.

Levene in Chapter 6 of his book Clinical Refraction and Visual Science, Butterworthâ€™s, 1977. Highly regarded as a diplomat and as a scientist, Franklin is generally acknowledged for all his ingenious contributions to many very practical inventions. He had talents and also numerous interests and his natural curiosity led to the search to discover ways to make things work better. One of his greatest innovations was â€œmy double spectaclesâ€� and Franklin has been quite appropriately recognized and universally admired as their inventor. Certainly among the most useful inventions of all time bifocals have serviced billions of people over the past 200 + years. Compound corrective lenses, usually bifocals or trifocals, and with increasing frequency, progressive multifocal length eyeglasses are the modern-day result of the remarkable evolution from Benjamin Franklinâ€™s original simple and practical creation. THE EVIDENCE SUPPORTING FRANKLIN 1). Benjamin Franklin was a hyperope who likely required eyeglasses originally in the 1730s. By the late 1750s he was usually described wearing them and they became an integral part of his face, at least for distance use.

Many paintings and contemporary sketches and satirical cartoons show him represented wearing his eyeglasses. He admitted that he could not â€œdistinguish a letter or even of large print without themâ€�. 2). The Library Company of Philadelphia, founded by Franklin and some of his friends, became Americaâ€™s first lending library. In its print archives there exists a 1764 political cartoon which depicts Franklin wearing an unusual pair of eyeglasses, interpreted by some knowledgeable people as bifocals because the upper portion of each lens appears different from the lower portion. Take a close look and decide for yourself. 3). Von Rohr and several others credit optician Samuel Pierce with making bifocals for Franklin. Pierce described people wearing bifocals in 1775 and he himself may have worn them in the 1760â€™s. Although this is all noted in the Leveneâ€™s chapter no hard evidence is presented. 4). Mr. H.

Sykes, an English optician living in Paris, with a business on the Place du Palais-Royale, wrote to Franklin April 24, 1779 and explained the delay in sending Franklinâ€™s order, complained he was having difficulty making the eyeglasses. â€œI should have sent your spectacles sooner, but in compliance with your favor of the 20th inst., have cut a second pair, in which I have been unfortunate for I broke and spoilt three glasses.â€�Sykes had apparently damaged them while â€œcuttingâ€� them in half. The word â€œcutâ€� is emphasized as opposed to the word â€œgrindâ€�. Even Sykesâ€™ charge for this service (18f a pair) was quite excessive when compared to the normal fee of making simple ordinary glasses. 5).

During his stay in Passy, outside of Paris, Franklin (serving as the American envoy to the Court of Louis XVI) described in a letter dated August 21, 1784 to his close friend and philanthropist George Whatley: â€¦â€¦.â€�I cannot distinguish a letter even of large print; but am happy in the invention of double spectacles, which serving for distant objects as well as near ones, make my eyes as useful to me as ever they were: If all the other defects and infirmities were as easily and cheaply remedied, it would be worth while for friends to live a good deal longerâ€¦..â€� 6). In a letter dated November 15, 1784 Whatley wrote back: â€œI have spoken to Peter Dollond about YOUR invention of double spectacles, and, by all I can garner,â€¦â€¦.â€� 7). Another correspondence with Whatley May 23, 1785 further explains Franklinâ€™s basic position on this matter.

Noted London optician Peter Dollond had stated they were only good for â€œparticular eyesâ€�. Franklinâ€™s reply is certainly very persuasive evidence that he was the inventor: â€¦â€¦â€¦â€¦..â€�By M. Dollondâ€™s saying that MY double spectacles can only serve particular eyes, I doubt he has not been rightly informed of their construction. I imagine it will be found pretty generally true, that the same convexity of glass, through which a man sees clearly at distance proper for reading, is not the best for greater distances. I therefore had formerly two pairs of spectacles, which I shifted occasionally, as in traveling I sometimes read, and often wanted to regards the prospects. Finding the change troublesome, and not always sufficiently ready, I had the glasses cut and half of each kind associated in the same circle, thus (his well-known drawing is in this letter which now resides in the Library of Congress). By this means, as I wear my spectacles constantly, I have only to move my eyes up or down, as I want to see distinctly far or near, the proper glass being always ready.

This I find more particularly convenient since my being in France, the glasses that serve me best at table to see what I eat, not being the best to see the faces of those on the other side of the table who speak to me; and when oneâ€™s ears are not well accustomed to the sounds of a language, a sight of the movements in the features of him that speaks helps to explain, so that I understand French better by the help of my spectacles.â€� 8). Whatleyâ€™s next reply dated July 22, 1785; â€¦â€¦â€¦.â€�The Dollonds are obliged by what you have been at pains to say, and describe of your double spectacles. They fully comprehend it at eh same time say, for such sight as yours are common. That therefore they only make for such as like yours when bespoke.â€� 9). Charles Wilson Peale painted Benjamin Franklin in 1785 and the painting is the only one showing Franklin wearing double spectacles. The bifocals are a prominent feature of this famous artwork. No earlier depiction of anyone else wearing bifocals is known to exist anywhere in the world!

This unique art treasure is at the Pennsylvania Academy of the Fine Arts in Philadelphia. 10). In 1788 Peale made his own bifocals, as noted in his diary for August 25th. These became quite helpful when he painted miniatures. â€œIt would appear that Charles Wilson Peale helped to popularize bifocals in America because he probably taught their method of manufacture to John McAllister, Sr. first American opticianâ€� (the Letocha article). 11). Correspondence from John Fenno, editor of the Gazette of the United States, to his wife March 8, 1789 described a meeting in Philadelphia during the last year of Franklinâ€™s life. The evidence in this letter points strongly to Franklin. It currently is housed at the William C. Clements Library, University of Michigan. â€œHe informed me that he had worn spectacles for 50 years.

He had them on and as they appeared to be differently constructed from any I had seen the circumstance led to some inquiry - each eye appeared to be formed of two pieces of glass divided horizontally â€“ he informed me that he had always worn such â€“ the upper part was to view distant objects, the lower to read with. â€¦.â€� 12). In 1790 Dr. William Rowley published the book A Treatise on One Hundred and Eighteen Principal Diseases soon after Franklin passed away. He quoted the May 23, 1785 letter to Whatleyâ€¦ â€œA species of spectacles has been recommended by the late Dr. Franklinâ€¦â€� Thus he was the first to inform the medical community of Franklinâ€™s invention. He also went on to say that he recommended double spectacles to some of his friends, â€œby whom they are highly approved.â€� 13). In the August 1791 issue of Massachusetts Magazine, the general public first learned of Franklinâ€™s double spectacles.

Lewis Leprelete wrote to the editors quoting the same May 23, 1785 letter from Franklin to Whatley announcing that â€œA species of spectacles has been recommended by the late Dr. Franklinâ€¦..as it is an important object, I have no doubt but you will be pleased to gratify the publick with it,â€¦â€� 14). President Thomas Jefferson communicated with John McAllister Sr. and also with Charles Peale in a fascinating group of letters between 1806 and 1808. referring to the Franklin bifocal on Nov. 12, 1806. This letter is held by the Library of Congress: â€œYou have heretofore furnished me with spectacles, so reduced in size as to give facility to the looking over their top without moving them. This has been a great convenienceâ€¦â€¦â€¦Those who are obliged to use spectacles know what a convenience it would be to have different magnifiers in the same frame. Dr.

Franklin tried this by semicircular glasses joined horizontally, the upper & lower semicircles of different powers, which he told me answered perfectly. I wish to try it and therefore send you a drawing No. 2 agreeably to which, exactly, I will ask another pair of spring frames to be made.â€� Jefferson had been in France during the 1784-9 period, being successor to Franklin as minister. Obviously he observed Franklin wearing his bifocals when they were together. Later in 1807 Jefferson showed his satisfaction with his new bifocals in a letter to Peale March 29th 1807. He noted that he had â€œadopted Dr. Franklinâ€™s plan of half glasses of different focal distances, with great advantageâ€� Jefferson wrote to McAllister on March 16, 1808 that he was â€œextremely satisfied with Dr.

Franklinâ€™s method of joining the spectacles by composing each glass of two half-glasses of different magnifying powers, and those you made for me answer positively except that the frames being circular, the glasses are always turning around and bringing the seam between the two half glasses in the way of the eye. To prevent this the frame should be oval.â€� McAllister had earlier replied to Jefferson, who was by then President of the United, that he had already made such glasses for members of the Peale family and instructed Jefferson how to measure the distance between his pupils and determine the focal length of his current glasses. 15). The well-known French optician-engineer Jean Gabriel Augustin Chevallier discussed the 'Besicles a la Franklin' in the Gazette de Sante (June 11, 1806) which was subsequently reprinted in his Conservateur de la Vue (1810) and later editions of this well known book. 16). Seventeen years after Franklin died, Charles Wilson Peale painted a portrait of himself wearing bifocals. 17).

John Isaac Hawkins, engineer and inventor of the trifocal in 1826, coined the term bifocal in 1824 and he credited Franklin with the invention of the bifocal. ADDITIONAL GENERAL POINTS OF INTEREST 1) The idea of a split lens or lenses of different powers in one frame was originally suggested by J. Zahn back in 1683 and also by CG Hertel in 1716. In both these instances however it was possibly for trial lenses and not for use as eyeglasses. Does anyone know what these lenses definitely were for? 2) Benjamin Franklin began to advertise eyeglasses for sale in his newspaper, the Pennsylvania Gazette, as early as 1738. With moderate hyperopia he would have found eyeglasses to correct farsightedness useful by this time, about age 30. 3) No double spectacles (split-lens bifocals) have ever been found among Franklinâ€™s possessions nor, for that matter, have any of his ordinary eyeglasses been found either.

4) Sir Joshua Reynolds (1723-1792), 1st President of the Royal Academy and an eminent artist, was known to be a myope. His famous self-portrait of 1788 shows him wearing silver turn-pin wig spectacles. He may have worn bifocals made by Dollond. However he was myopic and could merely take his glasses off to do reading and writing and possibly therefore even painting. 5) Benjamin West (1738-1820), 2nd President of the Royal Academy and another eminent artist, wore bifocals perhaps made by Samuel Pierce. But West was a hyperope and likely would not have required them until the early 1790s. West was thirty years younger than Franklin and likely too young to have required them earlier that Franklin. In 1824 Samuel Pierce recorded comments that West had worn bifocals for years. Any artist would have appreciated the usefulness of bifocals, especially as he/she grew older. Pierce commented that he had known â€œseveral painters and other artistsâ€� who had used bifocals when they reached 60 â€“ 70 years of age.

6) Since both Benjamin West and his teacher Sir Joshua Reynolds could have had bifocal spectacles in the mid-1780s it is easy to see why some historians have suggested that either one of them could have originally invented them. But neither West nor Reynolds ever spoke up that they had been the first to conceive of bifocals. Neither of them has been as directly linked with this invention as Franklin has. 7) Franklinâ€™s name has been typically associated with bifocals, not the name of West or Reynolds. This invention was attributed to Franklin during the lifetimes of both West and Reynolds. If either of them was the inventor or if either knew of an inventor other than Franklin, wouldnâ€™t they have said something about it? 8) The â€œLondon opticiansâ€� advertised pretty heavily. If they had invented something as interesting as bifocals, wouldnâ€™t one expect they would have mentioned it in their advertising? 9) Patents were granted to Addison Smith in 1783 and to J.R. Richardson in London in 1797 for what could be called an alternative to bifocals.

Each was comprised of an extra pair of lenses hinged to the main spectacles, the Addison Smith variety came down from above while the Richardson variety rotated in from the sides behind the distance correction, in order to correct for near work. Dutch painter Rienk Jelderhuis is shown in a portrait in 1791 wearing an unusual style of double glasses. He had invented these with the distance prescription fixed in a frame attached to the top of each reading glass. 10) Thus during Franklinâ€™s lifetime and shortly thereafter, imaginative opticians came up with several eyeglasses designs that could be used for both near and distance vision. Franklinâ€™s bifocals however gradually became the dominant form of combined eyeglasses, although there were some problems with them. Opticians had a challenging time grinding the seam edge perfectly flat and keeping the half lenses from falling out of the frames. Lenses also rotated in the round frame also creating a problem. Another great annoyance was the dirt that accumulated in the seam line between the two half lenses, causing a visible dark line at the transition ridge. 11) Here is a bit of trivia about U.S. presidents and glasses. H. R.

Brands in his biography of Andrew Jackson, writing about his first inauguration wrote "Jackson remained standing before the crowd. He wore two pairs of eyeglasses: one currently on his eyes, the other-his reading glasses-thrown on the top of his head" One can assume from this that Ben Franklin's bifocals were still not in common use by 1829. (per Paul A. Rittenhouse) 12) George Elkington (1801-1865) patented two pair together in the same frame with a 45 degree angle induced in the bottom pair. Therefore they were half eyes and also pulpit glasses. 13) Isaac Schnaitman (1795-1875) was a German immigrant to Philadelphia who patented in 1834 a one-piece bifocal which is in fact inverted (upturned). To create this he took a minus tool and ground a small round section at the top of a plus lens. 14) 1861 John Braham patented auxiliary glasses (front hangers or grab-fronts). 15) In the OAICC Newsletter July 1998, N.

64 â€œNow that the College of Optometrists is housed at 42 Craven Street in London it is of particular note that Benjamin Franklin, the Inventor of Bifocals, lived at 36 Craven Street, just a few yards away, from 1757 until 1772. ***This statement is, by itself, significant confirmation because this publication and its greatly admired and highly-respected editor Ronald MacGregor are considered authoritative to me - DAF) ADDITIONAL RESEARCH Two researchers who I admire and respect have also examined the available evidence regarding Franklin. Their conclusions were: Dr. Charles Letocha, York, Pa â€œIt seems most likely that Benjamin Franklin did invent bifocals, most likely when he was in London in the 1760s or early 1770s. As a rule Franklinâ€™s inventions were practical things to solve practical problems. These included the Franklin stove, the lightning rod, a flexible catheter, an odometer, and a long arm to retrieve books from high shelves. The bifocal fits very nicely into this Franklinesque list." Alan McBrayer, Charlotte, NC 1.

The primary sources by Franklin with his description were the genesis of his idea. 2. This invention became known in England in a widely-read book in 1789 and in America in 1790, and nobody stepped forward and claimed prior invention. Even English newspapers and books attribute bifocals to Franklin. 3. The seeming lack of real primary sources that show early use by others (Peale excepted). There are no primary source documents that place bifocals on any faces except Franklin and Peale before 1800. 4. ***The 1804 comments of William Jones, apprentice to Benjamin Martin, employee of George Adams, Jr. and his father's business, and partner in his own business. In A Journal of Natural Philosophy, Chemistry and the Arts, March 1804, Volume VII, page 194, he mentions â€œThe bisected glasses of Dr. Franklinâ€�. Jones spent nearly fifty years in the thick of the optical scene in England and in this statement he attributes the invention to Franklin. Jones worked at "W. & S. Jones", a very large optical manufacturer on Hobron Street.

They had a series of catalogs 1792 - c1810 that listed about every optical instrument available. Jones personally knew Franklin, was a member of the American Philosophical Society, and was very much at the top of the optical scene in Britain 1760 and then for the fifty years thereafter. He is about as "primary source" as it gets. If split bifocals pre-existed Franklin in England somewhere, Jones would have heard about it. His name can be professionally linked with virtually any prominent optician or scientist of his day. CONCLUSIONS Bifocals are attributed to Ben Franklin and he probably came up with the idea by himself. He did not produce them himself but instead had some optician in London or France make them for him. Franklin and his close circle of friends, including West and Reynolds, all probably wore them. Franklinâ€™s discovery of the bifocal is generally felt to have occurred in the early 1760â€™s.

Most hyperopic presbyopes don't go into bifocals until their early 40s so a most realistic earliest date, an educated guess regarding Franklin himself, would be while he was living in London and that started in 1757.It is only from his 1784 letter to George Whatley that we have Franklinâ€™s first statement (with his own drawing) to confirm his involvement. The 1789 Fenno letter is also quite important because it is unique in attempting to possibly date the invention. The bifocal was so typical of Franklinâ€™s many inventions - another practical, elegant, simple solution to a problem he carefully defined. â€œIt just seems so Franklin-esqueâ€�. The important thing to Franklin was always the idea â€“ it would make life simpler for an aging man â€“ â€œanother thing to be freely shared with all old men so that their lives might be made easierâ€� (from a famous quotation by Charles Snyder).

OTHERS WHO ARE ACKNOWLEDGED FOR THEIR KIND SUPPORT Alan McBrayer, authority on American eyeglass makers of the 19th century Adrian Whitcher and Jane Wess from the Science Museum John Alviti from the Franklin Institute Barbara Katus of the Pennsylvania Academy of the Fine Arts Jeffrey Ray of the Atwater Kent Museum Clayton Lewis and John Dann of the Clements Library Charlene Peacock and Jim Green from the Library Company of Philadelphia. Melissa Clemmer and Page Talbott from the Franklin Tercentenary, Ellen Cohn from the Yale University Library My good friend and advisor Dr. Charles (Chuck) Letocha Neil Handley of the British Optical Association Museum Stuart Green How Eyeglasses are Made How Eyeglasses are Made More Eye Information How Eyeglasses are Made Eye glasses are specially crafted lenses made to fit inside frames designed to hold them, and are useful in correcting or greatly enhancing a person’s vision. In discussions on how eye glasses are made, many often believe that the precursor of eye glasses was the magnifying glass. However, the history leading to the invention of eye glasses actually extends a lot further.

Anyone truly curious about how eye glasses are made may be interested to know that, as early as 4 BCE, people are believed to have used water to enhance or enlarge the appearance of small items that they wished to view more closely. It has also been noted that the Roman philosopher Seneca used a specially crafted water-filled orb to magnify the print contained in the many books he read. More than one thousand years later, Italian craftsmen produced solid glass lenses similar to today’s magnifying glasses to assist people with poor or declining vision. Variations of this design progressed over several years until the first eye glasses actually worn on the bridge of the nose were produced in Italy circa 1285. It is Benjamin Franklin who was ultimately credited with the invention of the bifocal lens useful in vision correcting. Franklin’s invention actually led to the type of eye glasses that are commonly worn today. Contrary to the name, today’s eye glasses are most often made of plastic. Prior to the 1950s, eye glasses were still being made with glass, but newer uses of plastic since then have proved to be a lighter, more comfortable choice for those who wear eye glasses.

In the United States, the Food and Drug Administration (FDA) and the American National Standards Institute (ANSI) strictly regulate the standards by which eye glasses are made. To assure that these standards are met, all manufacturers licensed to make eye glasses are also required to be members of the National Optical Association, which further enforces the rigorous standards of the FDA and the ANSI. The exact science of how eye glasses are made involves a very precise, very detailed system of events. After a patient’s eyes are tested to determine whether or not eye glasses are needed, if it is determined that eye glasses will be prescribed, a technician then has the task of figuring out the patient’s necessary prescription strength. A special computer is used in determining this and it prints the exact specifications for how to manufacture the prescribed lens for the patient’s eye glasses. The physical creation of the prescribed eye glasses then involves the technician comparing a pair of plastic blanks until an appropriate one is found for the patient’s prescription. The remaining prescription strength needed is then ground into the blanks at the back of the lens. Next is the blocking process, which is when the optical center of the eye glasses is located. More grinding sets the necessary degrees or curves that are needed to achieve the optical strength that the eye glasses need.

The lens is then shaped or beveled, and polished to perfection. While different types of plastics are used in making glasses, a very lightweight polycarbonate known as “Featherweight” is the most durable, the most popular, and the most expensive. Also, if a patient prefers tinted eye glasses, the lenses are specially treated before being finally inserted into whichever frames the patient has selected. Because of advances in technology and the materials used, today’s eye glasses are much more durable than in years past, and many people even regard them as fashion accessories. The History of Eyeglasses and Their Invention Is Debated Even Today Eyeglasses Trends History of Eyeglasses Eyeglasses have been mentioned or referenced numerous times throughout history. Many speculate that eyeglasses are almost as old an invention as written history itself, while others take a more conservative belief that eyeglasses were initially invented in the dark ages around 1200-1300 a.d. While there is no solid evidence as to who the initial inventor was, it wouldn’t be surprising if corrective lenses were “invented” multiple times throughout history until a point where the technology was finally passed down throughout multiple generations, eventually reaching the modern era.

Notable historical references to eyeglass discovery and invention Some believe the Egyptians and Assyrians were the initial inventors of optical lens styles, as they were depicted to have made use of magnifying stones to enlarge text and print. Notable roman philosopher Seneca was known to use water-filled objects as a means to magnify text for studying and reading as early as 4 B.C. While none of these societies formally invented spectacle style glasses, they all used magnifying technology for the purpose of vision correction and enhancing smaller images. Around the late 12th century A.D, Marco Polo reportedly stated that eyeglasses were widely popular among the wealthy upper class, although many people believe that the Chinese originally obtained the technology through the silk trade with the Middle East nearly one hundred years earlier. Around the similar time, european monks recorded having invented eyeglass spectacles, which were henceforth passed down throughout European and modern history. Further Development of Eyeglasses After the 13th century, eyeglasses were built with either convex or concave lens styles, which effectively cured either myopia (nearsightedness) or hyperopia (farsightedness).

While near and far-sightedness were the most prevalent eye conditions, many still suffered from astigmatism and presbyopia (both near and far-sightedness). Most credit Ben Franklin with inventing the first bifocal lens, which was able to correct vision both near and far away. Not long after the invention of bifocal glasses, George Airy was credited with inventing a lens style that corrected astigmatism. In more modern times, eyeglasses have developed many new technologies, specifically with lens curvatures and lens materials. Rarely are eyeglass lenses manufactured with glass anymore, and lenses are now thinner and lighter than ever before, while still retaining pinpoint accuracy (assuming proper prescription). Most eyeglass lenses are made out of plastic polymers, which offer greater flexibility, greater durability, and are safer for active wear. Be Sociable, Share!

Bifocal Glasses History - Invention of Bifocal Glasses BIFOCAL GLASSES Glass lenses, for use as magnifiers or for starting fires, date to about 300 BC, but the first eyeglasses to aid or correct vision were almost certainly invented in 1280 in Florence, Italy by the Dominican friar Alessandro della Spina and / or his friend, the physicist Salvino degli Armati. Prescribed for far-sightedness, the glasses had convex lenses and were worn by Armati, who had injured his eyes while performing light refraction experiments and discovered that it was possible to enlarge the appearance of objects by looking through two pieces of convex glass. It was in the early fourteenth century that concave lenses were used to correct near-sightedness. In fact, Pope Leo X was depicted wearing glasses, with concave lenses, in a 1517 painting by Raphael. Whereas early eyeglasses were made of polished quartz, by the sixteenth century developments in glassmaking made it possible to mass produce them from glass.

Bifocals, the combination of both concave and convex lenses for both types of vision correction, a top lens for distant viewing and a lower lens for reading, were developed around 1760 by the American statesman and inventor Benjamin Franklin. TO LEARN MORE Who Invented Eyeglasses? Who Invented Eyeglasses? More Eye Information Who Invented Eyeglasses? As early as 700 BC, the Assyrians used polished crystal to magnify objects. Ancient Egypt and Babylon used similar objects and the ancient Romans and Greeks filled glass spheres with water for the same purpose. Seneca, the Roman philosopher, wrote about filling transparent vessels with water in order to magnify objects seen through them. Emperor Nero, who reigned during Seneca’s lifetime, is said to have used the first monocle, an emerald held in front of one eye as a lens to better see at distances. Sometime between the 11th and 13th centuries, monks used reading stones to help them see the manuscripts they were illuminating. These reading stones were made by cutting glass spheres in half and holding them over the text or artwork needing magnification.

Roger Bacon, the forerunner of modern science, wrote of the magnification properties of lenses in 1262. His observations, based on experiments, were used by later scientists in the burgeoning studies of the natural sciences. In conjunction with the Age of Enlightenment, during which new ideas about scientific subjects like earth sciences and astronomy were developed, optics became an important topic. Italian Salvino D’Armate of Florence is credited with inventing the first pair of wearable eyeglasses in 1284. It is said a memorial once stood, honoring him, but it no longer exists. Others, like Alessandro di Spina, were also given credit for the first eyeglasses, and though doubt exists as to the actual inventor, all prototypes were probably invented in Italy late in the thirteenth century. The use of eyeglasses was depicted in several artworks created in the fourteenth and fifteenth centuries, giving credence to the existence of spectacles during this period. Hyperopia, or farsightedness, and presbyopia, the vision problem that develops with age, were the first eye conditions for which glasses were invented.

These armless convex-lensed glasses, called pince-nez, were pinched together to sit on the bridge of the nose. Over the years, various contraptions were used to hold the lenses, from a ribbon attached to the lenses and wrapped around the wearer’s head to lorgnettes that held the lenses atop a long handle. Others with attached handles that operated like scissors were called scissors-glasses. Edward Scarlett of Great Britain invented the first earpieces similar to what are used today. Lenses for nearsightedness, or myopia, weren’t discovered until later, when Nicholas of Cusa is credited with using concave lenses for this condition. In his 1604 paper on optics and astronomy, German astronomer Johannes Kepler offered a scientifically correct explanation of the effectiveness of concave and convex lenses to correct vision deficits. His treatise formed the basis of today’s optical science. In 1784, almost two centuries after Kepler’s writing, Benjamin Franklin invented the first pair of bifocals. Reportedly suffering from both myopia and presbyopia, Franklin was attempting to avoid the aggravation of switching between pairs of glasses to read or to see distant objects. His invention had a frame that held two lens sections together.

The idea of cementing these two lenses together was not conceived for another one hundred years. Since then, the technology for eyeglass lenses and frames has improved, contact lenses have been developed, and lasers are used to correct some vision problems. What was a tremendous mystery centuries ago is now an ordinary part of most people’s lives.

Question: Who is credited with the invention of bi-focal glasses?
Answer: BENJAMIN FRANKLIN